code: def testInvalidMaxLen(self):
      barFeed = self.__getFeed()
      lb = linebreak.LineBreak(
          barFeed[LineBreakTestCase.Instrument], 3, maxLen=4
      )
      lb.setMaxLen(3)
      with self.assertRaisesRegexp(
          Exception, "maxLen can't be smaller than reversalLines"
      ):
          lb.setMaxLen(2)
  
file_path: pyalgotrade/testcases/technical_linebreak_test.py
imports: import datetime
  from .None import common
  from pyalgotrade.technical import linebreak
  from pyalgotrade.barfeed import yahoofeed
  from pyalgotrade import dataseries
  from pyalgotrade import bar
  from pyalgotrade.dataseries import bards
label_desc: Use image node_id 7 for calling the LineBreakTestCase obj's underlying member method code with example usage: obj.testInvalidMaxLen() without return types